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comparison mod_http_upload_external/mod_http_upload_external.lua @ 2332:c2cf5b40b66d

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mod_http_upload_external: Variant of mod_http_upload that delegates HTTP handling to other server using signed URLs
author Kim Alvefur <zash@zash.se>
date Thu, 13 Oct 2016 18:57:15 +0200
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children d6badf56ab5f
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2331:611a787e6d08 2332:c2cf5b40b66d
1 -- mod_http_upload_external
2 --
3 -- Copyright (C) 2015-2016 Kim Alvefur
4 --
5 -- This file is MIT/X11 licensed.
6 --
7
8 -- imports
9 local st = require"util.stanza";
10 local uuid = require"util.uuid".generate;
11 local http = require "util.http";
12 local dataform = require "util.dataforms".new;
13 local HMAC = require "util.hashes".hmac_sha256;
14
15 -- config
16 local file_size_limit = module:get_option_number(module.name .. "_file_size_limit", 100 * 1024 * 1024); -- 100 MB
17 local base_url = assert(module:get_option_string(module.name .. "_base_url"), module.name .. "_base_url is a required option");
18 local secret = assert(module:get_option_string(module.name .. "_secret"), module.name .. "_secret is a required option");
19
20 -- depends
21 module:depends("disco");
22
23 -- namespace
24 local xmlns_http_upload = "urn:xmpp:http:upload";
25
26 -- identity and feature advertising
27 module:add_identity("store", "file", module:get_option_string("name", "HTTP File Upload"))
28 module:add_feature(xmlns_http_upload);
29
30 module:add_extension(dataform {
31 { name = "FORM_TYPE", type = "hidden", value = xmlns_http_upload },
32 { name = "max-file-size", type = "text-single" },
33 }:form({ ["max-file-size"] = tostring(file_size_limit) }, "result"));
34
35 local function magic_crypto_dust(random, filename, filesize)
36 local message = string.format("%s/%s %d", random, filename, filesize);
37 local digest = HMAC(secret, message, true);
38 random, filename = http.urlencode(random), http.urlencode(filename);
39 return base_url .. random .. "/" .. filename, "?v=" .. digest;
40 end
41
42 -- hooks
43 module:hook("iq/host/"..xmlns_http_upload..":request", function (event)
44 local stanza, origin = event.stanza, event.origin;
45 local request = stanza.tags[1];
46 -- local clients only
47 if origin.type ~= "c2s" then
48 module:log("debug", "Request for upload slot from a %s", origin.type);
49 origin.send(st.error_reply(stanza, "cancel", "not-authorized"));
50 return true;
51 end
52 -- validate
53 local filename = request:get_child_text("filename");
54 if not filename or filename:find("/") then
55 module:log("debug", "Filename %q not allowed", filename or "");
56 origin.send(st.error_reply(stanza, "modify", "bad-request", "Invalid filename"));
57 return true;
58 end
59 local filesize = tonumber(request:get_child_text("size"));
60 if not filesize then
61 module:log("debug", "Missing file size");
62 origin.send(st.error_reply(stanza, "modify", "bad-request", "Missing or invalid file size"));
63 return true;
64 elseif filesize > file_size_limit then
65 module:log("debug", "File too large (%d > %d)", filesize, file_size_limit);
66 origin.send(st.error_reply(stanza, "modify", "not-acceptable", "File too large",
67 st.stanza("file-too-large", {xmlns=xmlns_http_upload})
68 :tag("max-size"):text(tostring(file_size_limit))));
69 return true;
70 end
71 local reply = st.reply(stanza);
72 reply:tag("slot", { xmlns = xmlns_http_upload });
73 local random = uuid();
74 local get_url, verify = magic_crypto_dust(random, filename, filesize);
75 reply:tag("get"):text(get_url):up();
76 reply:tag("put"):text(get_url .. verify):up();
77 module:log("info", "Handed out upload slot %s to %s@%s", get_url, origin.username, origin.host);
78 origin.send(reply);
79 return true;
80 end);